First of all they say that mpg falls by as much as 40%, but do not compare it to how much a conventional car loses in the same test.

Second, almost any ad-hoc test such as this will get lower than the EPA test, since they aren't running the exact same simulated course for the highway and city tests. Maybe their test would show 20% lower than the EPA test which would make the portion attributable to the AC/defrost only 20%.

Finally, they don't say how long their test was. This is a big factor for hybrids since they generally need ~5 minutes to reach max efficiency. Running the AC/defrost increases this time slightly. While this is a real drawback (for people who mostly make only very short trips), there is not much that can be done about it. But it is silly to say that this is a "negative" since during the few minutes of warmup time they are getting about the same mpg as a conventional car. That's like saying I don't want a car that gets double the mpg of my car because it only get the same mpg for the first few minutes.

As hybrids get more and more popular there will probably be more and more attempts to nit pick at everything that is different.